Apparatus for tube bending



J.F.VVESLEY APPARATUS FOR TUBE BENDING Filed April 18, 1936 H A "Ulm s sheets-sheet 1 Aug. 9, 1938. J. F. wEsLEY 2,126,235

l APPARATUS Pon 'runs BENDING rn'ed April 1a, 193e s sums-sheet 2 V ORNEY.

BY' {wurm/HM Patented ug. 9, 1938 UNITED STAT E-s PATENT OFFICE ananas APPARATUS FOR TUBE BENDING n -Joseph Wesley,

ABundy Tubing Company, ,poration oLMichig'an Detroit, Mich., assgnor to Detroit, Mich., a cor- .Appucation'april1811936, serial No. 75.153 y of the-tube. It is also an object of the invention to provide an apparatus for so bending a tubeV that'the walls -of the tube, both inside and 'outsi'de of the curved formation, retain substantially their original smooth form.' There is, of course, a tendency in the bending operations heretofore performed, to roughen or disrupt.the smooth contour of the tube, particularly the metal on the inside of thecurve; what'is meant is that metalA on ltheinside of the bend form may be somewhat gathered, or perhaps the Word corrugated applies, due to the fact that this metal is under compression.

The present invention seeks to avoid this gathering, corrugating or roughening of the tube wall.

Of course, the metal of which radius upon` which the tube may be bent. The Aso-called Bundy" tube, which is now used extensively in the automotive industry, is formed of steel stock with the seams and plies thereof a tube is madel determines largely the minimum length of theV united by a lsealing metal, as for example copper.

Heretofore the bending of such tube has, from apractical standpoint, been limited to, bending on a radius about 11/2 times the diameter of the tube. The radius referred to is figured from the center of the bend to the axis of the tube; the diameter'A is iigured as the outside diameter of the tube..

By use of the present invention the -radius of the bend may be materially reduced, and yet a practicaland commercially acceptable article is provided. -One example is this: A Bundy tube for'med of double ply steel stock, sealed and coat-y edwithcopper, and having an outside diameter of of an-inch-has been practically and successiully bent through 180 `on a radius of slightl ly less than# 11'; of an inch. Thus itwill be noted that in this example the radius of thebend is approximately'that ofthe outside diameter of the tube. This, of course, is only one example and theinvention is not limited thereto, as the deviceA is capable of providing a better bend, even though the tube be bent on a relatively long radius, and the invention maylbe likewise used on bends of even a shorter radius.

In carrying out this invention the tube is subjected to a pulling or drawing action, that is to 1 say, the tube-ispulledo1"- drawn lengthwise as it is fashioned.l l

s claima '(01. iss-.40)

' detail.

Fig. v4 is an enlarged view showing a part of the Abending apparatus and with some parts 10 shown in section.

, Fig. 5 is a sectional view taken substantially on line 5 5 of Fig. 3.

Fig, 6 is a sectional view taken substantially on line 6--6 of Fig; 3.

Fig. 'I is a view ofthe apparatus illustrating the same in its position after having bent a tube through substantially 180.

Fig. 8 is a view illustrating an arrangement on the machine for making bends in a tube subse- 20 quent to the first bend therein.

Fig. 9 is a detailed view showing the former around which. the tube may be bent.

Fig. 10 is a view illustrating a length of tube with several bends therein. l

The apparatus may, of course, be used for bending tubing for any purpose. One such purpose is that of making a heat exchange device, as for example a condenser for a4 refrigerating or cooling mechanism. In Fig. 10 there is shown 30 a length of tubing I fashioned with bends 2, thus' at 9, is preferably such as to permit of lengthwise 40,.

adjustment of the arbor, in order that its opposite end may be properly located relative to a former. The opposite end of the arbor is shown at 8 in Fig. 4, and it is properly formed with a curvature since the tube is to be bent adjacent 45 this end 'of the arbor, with the metalof the tube lbending over the curved end of the arbor. A

tubing of desirable length as illustrated at I is 4passed over-the arbor and it may have the ns thereon as illustrated. The ins as shown are 50 disposed in groups spaced relative to each other, and the Atube is to be bent at those portions betweenthe groups of iins. Y

A suitable clamping meas is .provided for the free end of the tube, as shown in Figs. 3, 5, and 6,

This clamping means may include a relatively ilxed member I8 grooved to receive the tube, as shown in Fig. 5, and a movable clamping member I I is similarly grooved and capable of sliding movement in which it is guided by rollers I2 located in an elongated slot therein. Spring means I3 may be arranged in bored out portions of the block and may act upon the relatively fixed member I0 to normally separate these two parts of the clamping means. The member II may be advanced to clamping position by suitable means herein shown as being an eccentric I4 having a suitable operating handle I5 and operating on the back side of the member II. When the eccentric is rotated clockwise as Fig. 3 is viewed the clamp opens up and the tube may beinserted; when the eccentric is rotated counter-clockwise the clamping members move together and the tube is clamped therebetween. This clamp may be used for making the first bend in a length of tube. There is a stud I1 on the machine around which a bend of tube may be located as illustrated in Fig. 8 for taking subsequent bends in the tube, as will appear in more detail later.

The clamping means and stud are mounted upon a suitable support I8 which may be equipped with an operating handle I8. The support I8 carries the former means around which the tube is bent and the support I8 is pivotally mounted on the support 5. As shown in Fig. 2 a fulcrum member 28 is located in a suitable aperture in the support 5 so that it may turn therein, a plate 2| is located on the under side of the support I5, and cap screws 22l are taken through the plate 2|, fulcrum member 28 and into the member I8.

The former is mounted on the turning axis of the plate I8 and is arranged to turn with the plate. This former has a stud 24 located on the axis and passing through suitable apertures in the member I8, support 5 and plate 2|. The former may have a flange` 25 for resting upon the member I8. 'Ihe former has an upstanding body 26 with a reduced and grooved upper end 21, the groove being on a curve designed to substantially match the periphery of a tube to he bent, and the curve formation constituting approximately one-fourth of a complete circle. It will be noted by reference to Fig. 4 that the member 26, which is part of the former, is somewhat elongated in form, having a, curved surface 28 substantially on the axis and around which the tube is to be bent, and the body extends from the axis as at 29. A dowel pin 23 may pass .through the flange 25 to cause the former piece 26 to rotate with the plate I8.

The former is divided into two halves, the member 26 constituting the lower half. The upper half of the former is movable and comprises 't head 38 which may have a shape of elongated farm corresponding to the member 26 and having a grooved form 3| of approximately one-fourth of a circle, and when the portion 26 and the head 38; are brought together a groove is formed by the cooperating curved surfaces `which may be substantially semi-circular. The

I the' handle 38 is shifted clockwise as Fig. 9 is it may move as the tube is bent.

viewed the cam surfaces function to rock the rocker arm 32 in a counter-clockwise direction and thus the two parts of the former are clamped together. When the handle 38 is rocked counterclockwise the holding pressure is relieved, and on continued movement the rocker arm 32 is caused to rock clockwise to lift the head 38 from the former piece 26. This is accomplished by a lost play connection between the member 35 and the rocker arm. This connection may take the form of a link 48 mounted on pins 4| and 42 on the rocker arm and cam 35 respectively. In the closed position of fthe former the link may be loose on the pins as shown by the full lines in Fig. 9. As the cam is rocked counter-clockwise on its pivot point, the link, acting as a tension member, rocks the rocker arm 32 to open the former as indicated by the dotted line position of Fig. 9. The rocker arm 32 and its controlling cam are mounted for bodily movement on the member I8, as for example between brackets 44 and 45 carried by the member I8.

For the purpose of stabilizing the two former members when they are brought together in operating relation, thereis a pilot pin or stabilizing pin preferably located on the axis. This pin is mounted in one member and arranged to engage in an aperture in the other. The pin is shown herein at 46, which may be merely tightly iitted in the former piece '26 and which has an upwardly projecting part 41 which slidably ts into an aperture 48 in the head 38. Although the head 3,8 comes down into contact with the former 26 while travelling in an arc, the projecting piece 46 need not be long and the pin will i'lt tight, enough in the aperture to eiectively aid in holding the two former halves in proper operating relation.

There is a block or shoe 58 for engaging the tube on the side opposite that side fitted in the former groove, as shown in Figs. l and 4. This shoe may have some longitudinal extent for engaging a considerable length of the tube, as shown. Where the tube is provided with ns this block or shoe is constructed preferably so that For this purpose Athe block may be mounted on a bar 5| held retracted by a spring 52.' The bar may be provided with rollers 53 for a rolling action on a backing member 54.

The operation is as follows: The .arbor is mounted in an adjusted position so that its curved surface 8 is properly located for the bending of the tube therearound. With the head 38 of the former in raised position a length of tube is threaded over the arbor. This length of tube, as shown in Fig. '1, may have groups of fins thereon with spaces between the groups where the bends are to be made. At this time the support I8 is in the position as shown in Fig. l.l The, protruding end of the tube is then clamped between the clamping members |8 and II, and the head 38 of the ,former is lowered into position. The handle I8 is' now grasped and the support I8 is turned on its pivot in a counter-clockwise direction. In this action the former turns with the support. As the swinging of the support I8 progresses the tube is bent around the former and in this action the length of the tube which lies to the rear of the former, that is that portion of the tube on the arbor, is drawn or pulled forwardly on the arbor. The block 58 holds the tube on the arbor from swinging out of alignment. Fig. 7 illustrates the -relative position of the parts when the support |8 75 has been turned through substantially 180, forming substantially a 180 bend in the tube.

In bending the tube the wall thereof, which becomes the outside wall of the bend, forms over the curved surface of the arbor. This curved surface is properly shaped for this purpose. As the tube is pulled along the arbor in this action the forward fin in a group may abut the` block 50, but the block is permitted, by thel spring 52, to shift forwardly tensioning the springv as indicated in Fig. '7. Of course, a tube may be bent which is not equipped with finned stock, in which event the block may or may not be mounted for movement with the tube. After the bend has been formed and the parts are in the position as shown in Fig. 7, the 'clamp lll- II vis released, the upper half of the former is raised, and the support i8 is then shifted back to the Fig. 1 position. Now where a plurality of bends are to be made in a length of tube, as shown in.Fig. 10, the clamp Ill-II may not be used on succeeding bending operations. Instead, the previously .formed bend may be placed around the stud l1,

as shown in Fig. 8. Thus the stud serves to pull and draw the tube in succeeding bending operations.

It will be noted that in these bending operations the body of the tube is not held or clamped against movement, but to the contrary is permitted to shift or feed in a forward direction off of the arbor as the bending operation is being performed. In this way there is a minimum of compressionor crowding action of the metal of the tube on the inside wall, as the tube is more or less drawn around the former. 'I'here is, of course, a thinning of the metal constituting the outside wall of the bend, as this metal is under tension and is attenuated. By this invention both the inside and outside walls of a bend in a tube have a very smooth surface. The cross section of a tube, taken through such a bend, may be somewhat flattened, but there is in any event a uniform appearance with no abrupt indentations which may be in the nature of partial collapsing.

No forces are applied to the tube or the portion,l

grooves cooperating to form a groove around the surfaces of which a tube is to be bent, a rocker of the tube wall, at the outside of a bend, by anyv such force, is eliminated. As hasheretofore been pointed out, tubing can be bent on radii much shorter than as heretofore been feasible, and yet a commercial and practical structure is obtained.

1. In an apparatus for bending stock such as tube or the like, a' lower former part provided with a partial groove, an upper former part provided with a partial groove, with the partial grooves cooperating to form a groove around the surfaces of which a tube is to be bent, a rocker arm upon which the upper former part is carried, said rocker arm having a camv surface, a-

pivotally mounted operating member having a cam surface, said surfaces cooperating to hold the upper former part in operating position on the lower former part, and a lost motion connecvided with a partial `groove, with the partial or the like comprising, a rockable member, a.

former part non-rotatably secured to the rockablemember, a second former part, said former parts adapted to cooperate and shaped to provide a formingA groove around the surfaces of which the stock vis to be bent, an arm pivotally mounted on the rockable ymember for carrying the second former part, said arm being pivotal to bring the second former part into and out of operating relation with the first former part, means yfor holding the stock in cooperating relationship with the surfaces of said groove, operating means operatively connected with the pivoted arm and movable to swing the arm and shift the second former part toward and away from vthe rst former part and adapted to hold the second former part clamped in cooperating relationship with the first former part, and means for rocking the rockable member to effect similar rocking action of the former parts to bend the stock around the surfaces of the former parts.

4. In an apparatus for bending stock such as tube or the like, a former part, a second former part, said parts being shaped to provide a groove around the surfaces of which the stock is to be bent, a rocker arm upon which the second former part is'carried, a movable operating member, means comprising interengagingy surfaces and forming an operable connection between the rocker arm and operating member, which-interengaging surfaces have a cam action, whereby movement of the operating member in one direcsecond former part away from the i'lrst mentioned former part.

5. An apparatus for'bending stock such as a tube or the like comprising, a rockably mounted former part, means on the support carrying the second former part and operable to shift the same into and out of cooperating relationship with the first former part, means for holding the 'stock adjacent said former parts, clamp means on the supportfor gripping the stock so that the sto'ck is pulled lengthwise and bent around the former parts upon rocking movement of the support, and a projection on the support spaced from the former parts and adapted to be received in the bightportion of a bend in the stock, whereby in bending operations subsequent to the first, the stock is pulled lengthwise by the projection and bent around the former parts upon rocking movement of the support.

. JOSEPH FRANK WESLEY.

support, a former part xed thereto, a second v 

